US 2504982 A
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April ,1 R. s. HUNTER v 2,504,982
SIGNALING MIRROR Filed July 14, 1944 4 Sheets-Sheei 1 Big. 3.
led July 14, 1944 R. S. HUNTER SIGNALING MIRROR 4 Sheets-Sheet 2 i INVENTOR ATTORNEY April 1950 R. s. HUNTER 2,504,982
- SIGNALING MIRROR Filed July 14, 194.4 4 Sheets- Sheet 3 TARGET E129 9 511M INVENTOR fP/crmfio 5- HUNTER ATTORNEY AP?il 5, 1950 v R. s. HUNTER 2,504,982 SIGNALING MIRROR Filed Ju ly 14, 1944 4 Sheets Sheet 4 iNv NToR T @QH-ARD 5 HUNTER BY w v ATTORNEY' Patented Apr. 25,,1 1950 umirizo r 'yENT OFFICE as fors'ignaling on land, as between survey parties.
In the accompanying drawings-- Figure 1 is'aplan view-of my device. Figure 2 is a rear view.
Figure- 3 is a section mums-s of Figure: 2. F igure-4 *is zit-section on line 4 4 of Figure 1. Figure 5 is a plan view of" one ofin'ycolor screens.
Figure 6 is a side elevation, partly in section,
with one of'my color screens 'inposition. 7
Figure '7 illustrates the method of usingmysignali'ng mirror.
Figure 8 is a. diagrammatleview showingthe directions of reflection and'refraction of the sun to theatre:
Figure 9 is a" diagram-showing thedirections of reflection of sunlight from the mirror and surface of color screen. i
Figure 10 is a plan view of a signaling mirror provided with a dome-shaped retrodirective aiming reflector.
Fi ure 11 is a, section on line H-Il of Figure 10.
In these drawings- A mirror H has a reflecting back 12 in which there is a sighting opening I3. A retrodirective reflector l4 in a frame I5 is mounted on a hinge l6 having an attaching leaf I! which is secured to the rear of the mirror II by means of a tubular rivet l8 and mirror-engaging clamp iii. The tubular rivet l8 serves also as a means for attaching the mirror II by a suitable cord 20. My reflector I4 is shown in operative position in Figure 2 and infull lines in Figure 3, the latter view showing that the pintle 2| of the hinge i6 is at a distance from the mirror back less than the thickness of my reflector I4 and frame l5,
whereby the minimum angle between the mirror back and the frame I 5 is predetermined. The folded position of my reflector I4 is indicated in dotted lines in Figure 3, the frame I5 being secured by a pair of resilient catches 22 formed from the hinge leaf II. A color screen 23 (Figamended April 30, 1928; 370 '0. G. "757) ures 4 5- and 6) is detachably secured in front of my mirror H by opposed resilient clips 24 (Figures 3,, iand 6). Thecolor screen 23 is for use. in sending color signals. nd I have found the colors red, green and orange suitable for this use. Itwill be apparent from an inspection of Figures 6 and 9 that the color screen23 makes a. substantially linear contact with my mirror I! at the right-hand edge of these figures; that the cord 20 and clamps i9 hold it out otcontact with the mirror 1 I at other points- Thisis for the purpose of separating the colored beam of reflected light from the-white. light reflectedfrom the front surface of the color screen.
I .have shown in Figure 9- the manner in. which light reflected by the screenv will proceed in a different direction from that taken by light reflected from. the. mirror itself. This. separation of the colored and uncolored beams of reflected light .I have found necessary to avoidserious dilwtion of the color of the signal.
In Figures 10 and 11 the mirror 34. has a re,- flecting back 32 in which there is a sight opening 33. Directly behindthe opening 3315a domesh-apedaiming device. 34 provided. with a colored lining of Scotchlite 35 with a sighting opening 35 at the. apex of the device.
A "Scotch'ite sample which has been used to make experimental signaling mirrors is a thin flexible colored sheet in the face of which are imbedded numerous glass spheres substantially uniform in size. structurally, this material resembles a very fine grade of sandpaper. This trademark was applied to a product of the Minnesota Mining and Manufacturing Company, which product forms an element of the novel combination disclosed herein. This product is clearly disclosed in Patents Nos. 2,354.018 (Heltzer et al.), and 2,326,634 (Gebhard et al.)the latter disclosing a plurality of high-angularity retrodirective beads suitable for use in combination with other elements of my device. A more perfect device may be made by forming this retrodirective coating directly on the inner surface of my dome-shaped device 34.
The form of aiming device disclosed in Figures 1 to 7, inclusive, can be aimed only when the retrodirective button faces approximately toward the sun. It is necessary. therefore, that the signaler using this type of mirror turn it so that the button faces approximately toward the sun before he attempts to signal. v
With the modified aiming device illustrated in Figures 10 and 11, I have eliminated the necessity for this preliminary adjustment.
With my dome-shaped signaling mirror, the effective part of the retrodirective area will face the sun regardless of the rotation of the mirror with respect to the sun. The signaler need only sight through the opening 33 and tilt the mirror until the colored virtual image of the sun appears to be on the target. This materially expedites aiming the mirror as well as the subsequent holding of the beam on the target, which is very important when signaling to aircraft which move at high speeds across the sky and remain in view for very brief intervals.
It should be understood that the present disclosure is for the purpose of illustration only, and
that the invention includes all modifications and equivalents which fall within the spirit and scope 4 fleeting layer on the concave face of said cover including a multiplicity of small transparent spheres, a binder partially embedding said spheres, and light reflecting means incorporated in said layer.
5. A signaling device including a mirror with a window, a concave dome-shaped cover provided with a central sighting opening under and covering said window, a transparent flexible reflex light reflector sheet having substantial stretch allowing conformation, a layer of small transparent spheres partially embedded in the sheet to 1 provide a refracting light-returning layer of of the appended claims in which it is my intention to claim all novelty inherent in my invention as broadly as possible in view of the prior art.
What I claim is:
, 1. A signaling device including a mirror provided with a window, a concave dome-shaped 010- sure under and covering said window, a transpar-- ent light reflecting sheet supported on the concave surface of said dome and a multiplicity of precision retroreflectors in the form of high angularity retrodirective beads partially embedded in said sheet, the said closure being provided with a central sighting opening.
2. A signaling device including a plane mirror provided with a window, a concave dome-shaped cover provided with a central sighting opening under and covering said window, and a reflex non-scattering light reflector mounted on the concave face of said dome-shaped closure having a layer of small transparent spheres partially em: bedded in a reflecting binder.
3. A signaling device including a mirror with a, window, a concave dome-shaped cover provided with a central sighting opening under and covering said window, a reflecting binding material on the concave face of said cover, and a multiplicity of small transparent spheres partially embedded in said binder.
4. A signaling device including a mirror with a window, a concave dome-shaped cover provided with a central sighting opening under and covering said window, a non-scattering reflex-respherical lens elements, and light reflecting means incorporated behind the spheres to produce in combination therewith a non-scattering reflection of incident light when said sheet is mounted on the concave face of said cover.
RICHARD S. HUNTER.
REFERENCES CITED The ibllgnvingreferences are of record in the fileof this patent:
UNITED STATES PATENTS OTHER REFERENCES Time Magazine, page 40, January 3, 1944. (Copy in Div. 34.)
General Electric Review, pages 7, 8, and 9, May 1944. (Copy in Div. 34.)
Jungle, Desert, Arctic Emergencies, U. S. Army Air Force Flight Control Command, Safety Education Division. (Copy in Div. 34.)